Skyrim:Jarl

A Jarl is a ruler of one of the nine holds of Skyrim, equivalent to a Cyrodiilic Count. The jarls of Skyrim are largely independent, though they all swear fealty to the High King. All jarls have their own personal housecarl and steward, and some also have one or more thanes in their service. Many also have a court wizard in their service who is also sometimes the only spell merchant in town.

The game begins with nine jarls ruling the holds of Skyrim, each affiliated with either the Imperial Legion or the Stormcloak Rebellion. All except Elisif the Fair can be supplanted by a new jarl who is more supportive to the opposing force, based on your actions during the game. This depends on which force you choose to ally with in the Civil War, and jarls will be replaced when you help a side to capture a city they do not control, or through the negotiations made during Season Unending. Newly-instated jarls will gain a "Jarl" prefix to their name and move into the jarl's residence for that hold.

Deposed Imperial governments will generally seek refuge in the basement of the Blue Palace in Solitude, while deposed Stormcloak governments will go into exile in the Palace of the Kings in Windhelm. The jarl, their housecarl, their steward, and their family will be exiled together, and they will act unfriendly towards you.

Strangely, Jarl Laila Law-Giver's family will not be exiled with her should the Empire take Riften. Though Saerlund possibly remains due to his Imperial sympathies, her other son Harrald, who is a staunch Stormcloak, will remain also, and both will still behave as if the Stormcloaks control Riften (Saerlund will still warn of Stormcloak censure, for example). The same also applies to Jarl Balgruuf the Greater's children. They will instead hide in the basement of Dragonsreach, likely because their initially planned roles in The Whispering Door would break the quest should they be exiled.

If you join and finish the Stormcloaks questline, then Elisif the Fair will renounce her support for the Imperial Legion and will support the Stormcloaks, even though the jarls that supported the Legion are exiled to the Blue Palace. Her steward, Falk Firebeard, interprets the act of allowing Elisif to maintain her Jarlship as a masterful political stratagem on Ulfric's part.

Erikur and Hrongar were originally intended to become jarls, and still remain in the jarl faction. Erikur was to replace Elisif the Fair, who was to be murdered in Boethiah's Bidding. Hrongar was to replace Balgruuf the Greater after the latter was killed by his children during The Whispering Door. Somehow killing the incumbent jarls can trigger dialogue referencing the scrapped quests. Bryling is also in the jarl faction for unknown reasons, and has dialogue recorded to grant thaneships in Solitude, implying she was also originally intended to serve as jarl at some point, possibly as a Stormcloak replacement for Elisif or Erikur, judging by her seemingly pro-Stormcloak disposition.